Description: In the article the problems of the estimation of standard uncertainty of the average value of the series observations, which are connected with the unknown a priori their autocorrelation function are presented. It is show, that for the proper evaluation of the standard uncertainty of average value it is necessary to determine the effective number of the uncorrelated observations, which depends on the normalized autocorrelation function. It is indicated, that the evaluation of autocorrelation coefficients using the registered observations is accompanied by their essential statistical instability, which in turn leads to the uncertain determination of the effective number of observations. Conclusions relative to the decrease of the influence of the inaccurate evaluation of correlation function on the value of the standard uncertainty of average value are made.
Keywords: observation results, correlation, uncertainty evaluation